Rank in Judo
In Judo, improvement and understanding of the art is denoted by a system of ranks split into kyū and dan grades. These are indicated with various systems of coloured belts, with the black belt indicating a practitioner who has attained a certain level of competence.
The Kōdōkan Kyū-Dan ranking system 
Practitioners of Judo (柔道家 Jūdōka ) are ranked according to skill and knowledge of the art. Their rank is indicated by the colour of belt that they wear. There are two broad categories of rank: those who have attained a level of competency at which they are considered worthy of a black belt (黒帯 kuro obi ) and who hold dan (段) grades and those who are yet to attain that level and who hold kyū (級) grades. Those who hold dan grades are collectively termed Yūdansha (有段者) (literally "person who has dan") and those with kyū grades are Mudansha (無段者), literally "person without dan".
This ranking system was introduced by Kanō Jigorō, the founder of judo, in 1883 and the first dan grades were awarded to his students Saigō Shirō and Tomita Tsunejirō. Since then it has been widely adopted by modern martial arts.
As initially designed, there were six student grades ranked in descending numerical order. Beginners were given the rank of sixth kyu (六級 roku-kyū ) and wore a light blue belt. Once they had passed an elementary level of instruction, they were promoted to fifth kyu (五級 go-kyū ), when they would adopt the white belt. This they wore through fourth kyu (四級 yon-kyū ). The remaining three grades (third kyu (三級 san-kyū ), second kyu (二級 ni-kyū ) and first kyu (一級 ik-kyū ) were all indicated with brown belts (for seniors) or with purple belts (for juniors).
1st kyū is the last kyu rank before promotion to first degree black belt (shodan). There are ordinarily 10 dan ranks, which are ranked in ascending numerical order, though in principle there is no limit to the number of dan ranks.
Highest ranking jūdōka 
Kōdōkan graded jū-dans 
The ninth ("kudan") and tenth degree black belt (jūdan) and, theoretically, those higher have no formal requirements. Only fifteen individuals have been promoted to the rank of Kodokan 10th dan. On January 6, 2006, three individuals were promoted to this rank simultaneously: Toshiro Daigo, Ichiro Abe, and Yoshimi Osawa. This is the most ever at the same time, and the first in 22 years. No one has ever been promoted to a rank higher than 10th dan, but theoretically the Judo rank system is not limited to 10 degrees of black belt. The original English language copy (1955) of Illustrated Kodokan Judo, by Jigoro Kano, says:
|“||There is no limit...on the grade one can receive. Therefore if one does reach a stage above 10th dan... there is no reason why he should not be promoted to 11th dan.||”|
However, since there has never been any promotion to a rank above 10th dan, the Kodokan Judo promotion system effectively has only 10 dan ranks. There have only been 15 10th dans awarded by the Kodokan in the history of Judo.
|Name||Lived||Date of promotion|
Variations in rank structure 
Although dan ranks tend to be consistent between national organizations there is more variation in the kyū grades, with some countries having more kyū grades. Although initially kyū grade belt colours were uniformly white, today a variety of colours are used. The first black belts to denote a Dan rank in the 1880s. Initially the wide obi was used; as practitioners trained in kimono, only white and black obi were used. It was not until the early 1900s, after the introduction of the judogi, that an expanded colored belt system of awarding rank was created.
Belt colors 
See List of judoka
In Japan, the use of belt colors is related to the age of the student. Some clubs will only have black and white, others will include a brown belt for advanced kyū grades and at the elementary school level it is common to see a green belt for intermediate levels.
For dan ranks, the first five are colored black, 6th, 7th, and 8th dan have alternating red and white panels (dandara), and for 9th, 10th and 11th dan the belts are solid red. The final Dan is the twelfth dan, this is usually coloured white along with a judoka's first belt, however the highest dan reached in judo remains 10th dan. However, holders of grades above godan (5th dan) will often wear a plain black belt in regular training.
Some countries also use colored tips on belts, to indicate junior age groups. Historically, women's belts had a white stripe along the centre.
Examination requirements vary depending on country, age group and of course the grade being attempted. The examination itself may include competition and kata. The kyū ranks are normally awarded by local instructors (sensei), but dan ranks are usually awarded only after an exam supervised by independent judges from a national judo association. For a rank to be recognized, it must be registered with the national judo organization or the Kodokan.
Brazilian belt rankings are normally white, blue, yellow, orange, green, purple, brown and black (6th, 7th, and 8th dan may wear alternating red and white panels, and 9th and 10th dan holders may wear solid red belts). Additionally, a grey belt may be given to very young judoka (under 11 or 13 years old) just before the blue. Sometimes, competitors are organized into two categories depending on grading; the first is from white to green, and the second is purple through black.
In Canada belt rankings for Seniors are, in ascending order: white, yellow, orange, green, blue, brown and finally black. Belt rankings for Juniors use white-red, white, white-yellow, yellow, yellow-orange, orange, red- green, green-blue, blue, blue-brown, and brown.
United States 
In the US only senior players (adults, usually those age 16 and over) are allowed to earn dan levels, signified by wearing a black belt. The USJF and USJA recognize dan grades awarded by the other organization. Advanced kyū levels can be earned by both seniors and juniors (children under the age of about 16) and are signified by wearing belts of various colours other than black. The order of belt colours can vary from dojo to dojo, depending on the dojo's organizational affiliation.
For senior players, both the United States Judo Federation (USJF) and ) the United States Judo Association (USJA) specify six kyū, as listed in the table. The USJA requires "Beginners" (not a kyū) to wear a white belt until they test for yellow belt. The USJA also recommends wearing a patch specifying the practitioner's level. This is true for both kyū and dan levels.
The USJF Juniors ranking system specifies ranks to 11th kyū (jūichikyū). The USJA Juniors ranking system specifies twelve levels of kyū rank, beginning with "Junior 1st Degree" (equivalent to jūnikyū, or 12th kyū) and ending with "Junior 12th Degree" (equivalent to ikkyū). As with the senior practitioners, the USJA recommends that juniors wear a patch specifying their rank. When a USJA Junior reaches the age of 17, their conversion to Senior rank is:
- Yellow belt converts to 6th kyu (rokyu)
- Orange belt converts to 5th kyu (gokyu)
- Green belt converts to 4th kyu (yonkyu)
- Blue belt or higher converts to 3rd kyu (sankyu)
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